For a normal distribution,
a. what z-score separates the highest 10% from the rest of the scores?
b. what z-score separates the highest 30% from the rest of the scores?
c. what z-score separates the lowest 40% from the rest of the scores?
d. what z-score separates the lowest 20% from the rest of the scores?

1.282, -0.5244,...

Step-by-step explanation:

We know that Z is a standard normal variate with mean =0, and std dev =1

a) z-score separates the highest 10% from the rest of the scores

= 90th percentile = 1.282

b) z-score separates the lowest 30% from the rest of the scores

= 30th percentile = -0.5244

c) z-score separates the lowest 40% from the rest of the scores

= 40th percentile = -0.2533

d) z-score separates the lowest 20% from the rest of the score

=20th percentile = -0.8416

75

step-by-step explanation:

answer: -10

step-by-step explanation:

s(t) = 1 - 10t

s(x) = 1 - 10x

s(x + h) = 1 - 10(x + h)

            = 1 - 10x - 10h

s(x + h) - s(x) = 1 - 10x - 10h - (1 - 10x)

                      = 1 - 10x - 10h - 1 + 10x

                      = -10h

= -10